


The Prince and the OctoCas

by whelvenwings



Category: Supernatural
Genre: M/M, Merman Dean, Octopus Castiel, underwater au
Language: English
Status: Completed
Published: 2015-02-14
Updated: 2015-02-14
Packaged: 2018-03-12 21:51:07
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,414
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3356576
Author URL: https://archiveofourown.org/users/whelvenwings/pseuds/whelvenwings
Summary: <blockquote class="userstuff">
              <p>Castiel is an Octoperson, living in the crystal city of his people. But every day, he secretly goes to visit the city of the Merpeople - never to speak to them, of course, only to watch. And if he likes to watch one particular Merman in particular - well, there's no harm in that, right? It's not as though the Merman will ever know that he exists...</p>
            </blockquote>





	The Prince and the OctoCas

Cas moved across the ocean floor, being careful not to go too fast. He didn’t want to draw attention to himself.

This was always the hardest part: getting out of the city.There were eyes everywhere, questioning and noticing and judging. Cas wrapped one of his tentacles around his hand to calm his nerves as he cleared the outer suburbs of Halite, great underwater city of the Octopeople.

It was a beautiful place, with hanging seaweed gardens and buildings made from the coveted clouded crystals which only formed in the trenches and grottoes deep beneath the city itself. The great Governmental Residence’s translucent walls were lit from within by luminescent jellyfish, carefully corralled and replenished daily. It was a city of grandeur, magnificence and ostentation.

Cas hated it.

He tried very hard not to. It was his  _home_ , he reminded himself. It was where he belonged. And yet, just lately – it was crazy, but he’d been starting to feel as though – as though just perhaps, he belonged somewhere quite different.

It was impossible, of course it was – and dangerous, too. If a high-ranking Octoperson heard how often Cas was sneaking out of the city to go visit – the  _other_ place – he’d be put on trial in front of the entire city. That was why this was the last time he was going. It was foolish to put himself in danger, just so that he could go and stare at Merpeople.

Well, Mer _men._

Well – maybe _one_  Merman, in particular.

 _This is the last time,_ Cas reminded himself sternly.  _No matter if I see him or not. This is the last time._

It was a solemn promise, one that he fully intended to keep. The fact that he’d made the same promise the last four days in a row was something that he chose to carefully ignore.

Cas upped his speed, moving across the sandy ocean floor, feeling his hair twist and curl around his ears in the current. His black tentacles were getting stronger every day from the exercise – the Merpeople lived at least a league from Halite, and most of it was uphill. One of the many things that Cas preferred about the other city was how much closer it was to the surface; it was wonderfully light compared to the shaded, glowing home of the Octopeople.

Cas was moving fast, watching the ground ahead of him for sharp rocks that could cut the soft undersides of his tentacles – moving so fast that he didn’t even see the Octoperson in his path until he almost ran into him. He skidded to a halt, his heart beating quickly in his chest, his hair fluttering with the force of the halt.

 _Cas,_ Michael signed, only using the very tips of his tentacles to sketch a disdainful greeting. Cas responded quickly, making his gestures much wider and more elaborate. Michael was extremely high up in the Octopeople Government; Cas had only ever seen him at a distance, standing high up on a podium to communicate with the entire city on festive days and important occasions. He was astonished and slightly terrified that Michael even knew his name.

 _Where are you going?_ Michael signed. Cas twisted one of his back tentacles around his hand nervously.

 _To collect shale,_ he responded, twisting his tentacles in the complicated gesture for the sharp, stratified rocks that the Octopeople used as tools.

 _Why?_ Michael asked, a swift downward slash of his strongest tentacle that sent Cas’ heart thumping painfully; trying to stay calm, he improvised:

 _I want to try to make a spear._ He knew as soon as he’d finished signing that this had been the wrong answer. Michael’s face was as flat and unmoving as all the Octopeople’s, but his tentacles were swirling ominously.

 _Octopeople do not need spears. We have tentacles. Spears are the weapons of the Merpeople,_ Michael signed, flicking a contemptuous tentacle tip at the end to show his disgust.

 _I know,_ Cas signed back quickly, trying to repair the damage.  _I thought that if I could make one, I could figure out how to defend against it. For the next skirmish._ He kept his signing brief and sincere, meeting Michael’s eyes without blinking. Michael couldn’t know that he never volunteered to go out for the skirmishes with the Merpeople, could he? Of course he was always there to help when the Raiding Parties came back with the injured, but the thought of using his tentacles to hurt – or to smother – he almost physically flinched at the thought, but tamped down the impulse. After a moment of staring, Michael twitched an approving tentacle.

 _Good idea,_ he signed.  _I will be interested to hear your findings._

With that, Michael brushed past him, and Cas was alone. He took a few moments to breathe. Michael was a lot bigger and more powerful than he was, and even though Cas did have agility on his side, he wouldn’t have been able to put up any kind of struggle if Michael had realised that he was up to no good, and had decided to take him back to the city for questioning.

After a minute, Cas began to move again. He checked over his shoulder for any sign of Michael following him as he glided past the shale deposits, ignoring them entirely and continuing on the path that he was beginning to know all too well. He’d hardly been able to believe his own foolishness the first time he’d decided to come out here – he’d been daydreaming, enjoying the novel sensation of warmer, lighter water as he climbed the sandbanks and scaled the rocky cliffs, roaming further and further in search of edible seaweed – and then, suddenly, he’d heard noises. Vocalisations, like the whales made, but much higher and sweeter and more varied. Cas should have gone back, should have pretended he’d heard nothing and returned to Halite – but then he’d cautiously glided up a small coral outcrop, peered over the top, and seen –

Merpeople. Merpeople, everywhere.

Cas had ducked down, his hands shaking, his tentacles whipping in distress; he’d been on the point of fleeing. If the Merpeople had seen him, he’d have been killed on sight by those famous shale spears. And yet – even now, Cas couldn’t understand what had made him do it – he’d stayed for one quick peek more over the top of the coral. And then another, and another. Before he knew it, he’d been there for hours, watching the Merpeople as they swam and called to each other. And then he’d gone back the next day, and the day after that.

A month later, and here he was. He’d come every day that he’d been able to get away. He’d studied the Merpeople’s city as closely as he could at such a distance; from what he could tell, the buildings seemed to be made mostly of the same mix of living coral and anemones that populated the outcrop where Cas hid every time he came. Their waving fronds made the walls and outlines seem slightly blurred, a huge contrast to the sharp crystalline edges of Cas’ home.

It wasn’t only the architecture that kept Cas interested, though. Merpeople were going in and out of the city every day, and there were usually lots of them on the flat plateau of sand between Cas’ outcrop and the city walls; they liked to lie together and sun themselves, or throw objects at each other – it had taken Cas a while to realise that this was meant playfully – and all the while, they’d be vocalising at each other. They never seemed to stop talking. To Cas, coming from a city where communication was silent, they seemed raucous and terrifying to start off with. Before too long, though, he found himself getting used to it, even liking it.

Today, Cas arrived at his coral outcrop, and scaled it quickly. He didn’t bother to exercise too much caution these days; his initial fear of discovery had waned. Most of the Merpeople were too busy playing or talking to even look in his direction.

He hooked his tentacles into their well-worn spaces, careful not to damage any of the coral plants and always on the lookout for poisonous fish lurking amongst the fronds. He lifted his head slowly over the top of the rock, wondering if he’d be lucky – if today, he’d see his favourite Merman.

It was stupid to have a favourite, of course, and Cas was fully aware of it. He didn’t know any of the Merpeople, and if any of them knew him, they’d probably want to kill him. And yet, as soon as Cas had laid eyes on this  _particular_ Merman, he’d felt a connection to him, a warmth. Maybe it was the way the Merman carried himself, graceful and agile but not afraid to make a fool of himself – Cas had waved his tentacles so hard he thought he’d get a cramp when the Merman had been playing somersaults with the others, and had accidentally cartwheeled right into the city wall, bashing his head and making himself go cross-eyed. He had a powerful tail; Cas could see the difference now in the Merpeople’s anatomies, some of them muscular, some of them sinewy, some of them chubby. His favourite Merman’s tail was strong and large, an iridescent brown-green colour that seemed different to the usual blues and emeralds, or at least to Cas’ untrained eye. His upper body was thickset, his arms muscular, and his face – well, Cas hadn’t been able to check from close-up, but from what he could make out, his favourite Merman was something quite special.

And he didn’t seem to be the only one who thought so. Whenever his favourite Merman appeared (which he’d done three times so far, when Cas had been watching), all the Merpeople around him always performed the same odd gesture – crooking themselves over at the waist, inclining their heads and looking down at the ground. The Merman seemed used to it; Cas wondered whether perhaps that was his name, and he was one of the few Merpeople called by a gesture, rather than a spoken word. Like me, Cas thought. Like Octopeople.

And now today, staring out over the sandy plateau, Cas felt disappointment beginning to sink over him until – he clenched his fists – there he was! The Merman was fairly close to Cas today, with a large bunch of friends surrounding him. Cas settled down, resting his chin on his dominant tentacle as he watched the group start throwing a weighted ball between each other. Normally, he’d be trying to figure out the strategy and aims of the game – but today, his focus wasn’t on the game’s intricacies at all; he only had eyes for his favourite, who was right at the centre of the action. He kept making the same vocalisations over and over – maybe calling names, Cas thought? One of his friends threw him the ball and he jinked left and right around another one of them before passing it on. Cas admired the ease with which he swam, and the strength of his throw; he glanced down at his own arms, made strong by years of work in the crystal mines. Maybe he wouldn’t be so bad at this game that they were playing.

For a moment, Cas allowed himself to fantasise. He was out there on the plateau, playing with the Merpeople. He threw the ball to his favourite Merman, picking out an almost impossible pass, and the Merman was so impressed that he swam over to Cas and threw an arm around his shoulders, making those deep, throaty vocalisations that he made whenever he was happy…

Cas tugged himself back to reality. There was no use in wishing for impossible things. It  _had_  to be enough that he got to be here, watching the Merpeople, learning about them from afar. No one could ever know, especially not his favourite. Cas didn’t think he could stand to see the hostility in the Merman’s eyes if he ever laid them on Cas, and saw his tentacles, and his smooth, emotionless face. He’d be repulsed, and that would hurt terribly. Probably not as much as the spear that the Merman would then put through his chest at the first opportunity, but pretty close.

The Merman made a loud call, his arms in the air and his teeth bared. Cas had noticed that the Merpeople frequently did this when they seemed to be content or excited; it was just another bullet point on the list of things he didn’t understand at all about Merpeople culture. Why would they show their teeth to each other when they were happy? It couldn’t be a threat, could it? Castiel watched his Merman doing it, and tried it himself – curled up his top lip, stiff with disuse. It felt counter-intuitive, but Cas thought he could get used to it. The next time that his Merman did it, Cas did it again, too, and waved his tentacles happily.

The game that the Merpeople were playing was drifting slowly across the plateau, towards the place where Cas was hiding. It happened so gradually that Cas didn’t realise how close they’d become, until one of the Mermaids yelled loud enough to startle him. He ducked down lower, so that he was only just able to peer over the top of the coral. Part of him hoped frantically that they’d back away, and yet – his Merman was closer than ever, and for the first time Cas could see clearly the colour gradient of his scales, the sandy brown of his hair, the strange red markings on one of his shoulders –

The Merman took his eyes off the game for a moment, going completely still, his eyes slowly roving over the coral outcrop where Cas was hidden. His eyebrows were drawn low, an expression that Cas hadn’t seen before. Cas didn’t move, barely breathed; had the Merman seen him? Why else would he have stopped? Cas wanted desperately to flee, but he was sure the movement would catch the Merman’s attention. He stayed as still as he could, not even blinking. For a heart-stopping, drawn-out moment, the Merman’s gaze passed right over the place where Cas lay; and then he moved on, and quick as an eel Cas ducked low, spinning around so that his back was pressed against the coral, his tentacles gripping onto their rocky holds.

He closed his eyes and reran the moment when the Merman’s gaze had passed right over him. Had their gazes locked for a second, albeit unknowingly? Why had the Merman even stopped to look? Had he somehow – sensed that someone was here? That was impossible, surely. And yet – the way the Merman had held himself so still, his eyes seeking, searching….

It hardly mattered, Cas thought, putting those thoughts away for later. The important thing was that he hadn’t been caught. He’d had a near brush, though, and it would probably be best not to push his luck by staying longer; it was only a matter of time before the Merpeople and their game came even closer to the coral outcrop, perhaps even close enough to see him. Yes, it was definitely for the best that he left now. Cas prepared himself to leave, loosening his hold on the rocks –

And that was when the weighted ball came sailing over the top of the coral, and landed neatly in Castiel’s two front tentacles.

For a second he simply stared at it, unable to believe what he was seeing. He turned it over in his tentacles, feeling the softness, the strange stitching over the seams, the weight of it that stopped it floating to the surface –

And then Cas heard the shouts and calls from the other side of the coral, and realised with a spasm of fear through his chest that he was in horrible danger. All too soon, one of the Merpeople was going to come swimming over the top of the coral in search of the ball; he had seconds to move…

Too late. Cas could hear the low, rough voice of a Merman, getting louder and louder as he approached. Cas did the only thing he could think of – threw the ball away, hard, and then buried himself as far into the coral as he could. His tentacles did their best, taking on the appearance of the rock to which he was clinging; anemone fronds waved in front of his face, hopefully breaking up and disguising his torso too. Cas felt his hair move as the Merman passed overhead, risked a glance up and felt his heart stop completely for a full second. The tail he’d seen was brown-green, shining and beautiful. It was his favourite Merman who had come to collect the ball.

For one insane moment, Cas felt the urge to move, to draw the Merman’s attention, to be  _seen_ by him, just once – but then reality reasserted itself, and he was in fear’s grip once again as he watched the Merman swim over to where the ball had come to rest after Castiel had thrown it, and pick it up easily. Cas wriggled slightly, doing his best to ignore the tiny fish that had congregated around one of his tentacle tips. The Merman turned around, ready to swim back, just as the boldest of the fish nibbled curiously at one of Cas’ suckers. Cas stayed completely still, desperately fighting the urge to bat the fish away. The Merman had paused, again; his eyes were wandering over the coral, his eyebrows drawn down just like before.

 _Swim away,_ Cas thought desperately.  _Leave!_

But the Merman didn’t. He held the ball loosely in one hand, his gaze slowly zeroing in on the place where Cas was hiding, getting closer, and closer, until – inevitably, horribly, wonderfully, terrifyingly – fulfilling all Cas’ wishes and fears at once – his eyes met Cas’, and locked with them.

For a moment, neither one of them moved. Eventually, very slowly, the Merman tilted his head to one side, and finned the water gently, so that he moved a little closer. He started making sounds, his mouth moving – Cas hadn’t realised how much the Merpeople’s lips shaped the sounds they made to each other until now. Cas couldn’t read the Merman’s expression, but there was a softness in his eyes and body that didn’t seem to suggest immediate threat – oh, but of course, Cas realised. The Merman had only made sense of his top half. He thought that Cas was a Merperson, hiding in the coral.

Maybe if Cas just stayed still, the illusion wouldn’t be broken, and the Merman would leave him alone, Cas thought desperately. His heart was beating painfully in his chest, and he was struggling to breathe through his panic. The Merman was talking again, now, a little louder, and coming a little closer. Looking into his eyes with a little terrified frisson of excitement, Cas didn’t see the kind of creature who was going to give up and leave. This was both exactly what Cas had hoped, and the exact opposite of what he wanted.

Cas and the Merman were silent and still, watching each other. The Merman was, if anything, even more stunning close-up than he had been from afar, with big green eyes and full, soft lips. Cas found himself wishing desperately that he had time to get to know the Merman’s face, to learn it, map it out, understand it… but that was impossible. Eventually the Merman was going to realise that Cas was not one of his own; it might as well be now, when Cas wasn’t outnumbered and still stood a slim chance of escaping with his life. Cas took one last look at his Merman’s face as it was – soft, wide-eyed, not hostile – and then he moved, his tentacles losing their sandy colouration and returning to black as he drifted down the side of the coral. He moved as slowly as he could, trying to seem non-threatening.

The Merman’s face changed completely. His eyes went huge, and his mouth formed a perfect O; he made a little sound, which Cas could only guess was one of shock – or perhaps disgust, he reminded himself, wrapping one of his tentacles around his arm. The Merman was looking Cas up and down, his body frozen almost completely still, his tail paddling the water just enough to keep him upright. Cas, for his part, stared back, waiting for the Merman to strike, to yell, to swim away. But for some unknowable reason, he did none of those things. He simply stared, and Cas stared back.

They were so much closer than ever before – Cas was barely ten feet from the Merman, and now that he’d drifted down the side of the coral outcrop, they were at roughly the same height. The Merman was a little taller, although Cas’ tentacles were folded beneath him, resting on the sand. One of them was still wrapped tight around his own wrist for comfort, and the others were twitching and slashing anxiously; Cas did his best to repress the spasms, aware that they might make him seem more hostile or frightening. He met the Merman’s eyes, and saw in them a perfect mirror of his own emotions: fear, confusion, and just a pinch of wonder. It made his heart skip a beat, and put a little flutter in his stomach. The Merman – his  _favourite Merman_ – was looking right at him, and he wasn’t backing away. Or calling for his friends. Or looking for the nearest sharp object.

The tiny corals and anemones of hope that had been slowly growing over Cas’ crystal heart waved their fronds, and stretched a little into the new space of possibility.

After a moment, the Merman tentatively bared his teeth at Cas, and made a few sounds. Cas waved his back tentacles uncertainly. The Merman was obviously waiting for a response, but Cas could make no sound, and there was no way that a Merperson could possibly understand the Octopeople’s signing. Perhaps it was worth a try, though?

 _My name is Cas,_ he tried.  _I am an Octoperson._

The Merman watched his tentacles move, closing his mouth and bringing down his eyebrows. Cas wondered if lowered eyebrows entailed concentration, or – more likely – confusion. So he didn’t understand signing, then. Cas cast about for something, anything they had in common – a gesture, an expression –

Well, there was always the bare-the-teeth. It was a risk; Cas didn’t understand what it meant. What if it were incredibly rude to use to a stranger? No, he couldn’t use it. There must be something else…

Cas thought suddenly of the gesture that the Merpeople always performed when they first saw this Merman – the folding of their bodies, bowing over like seaweed strands in a current. Cas had thought that perhaps the gesture was the Merman’s name. Well, there was only one way to find out.

The Merman was still watching him; his body seemed more tense than before, and his eyes were shifting warily from side to side. Cas slowly raised his two tentacles and waved them softly, automatically signing reassurance – and then, carefully, hesitantly, he bent at the waist and inclined his head, staring down at the ground.

He held the pose for a few seconds, and then looked back up at the Merman. His face was back to its initial ‘O’ expression, the one that Cas hoped was surprise and not revulsion. Cas signed reassurance again, and then bent forward a second time, hoping that this was working.

 _Just don’t kill me,_ he signed, as he straightened. He knew the Merman wouldn’t understand, but he couldn’t help making the request.  _Please don’t kill me. I’m not your enemy. I promise that I mean you no harm._

Between each sentence, Cas bowed over again, saying what he hoped was the Merman’s name. After the third time, the Merman was showing his teeth again, which Cas took as a good sign. He stopped moving for a moment, twirling his dominant tentacle thoughtfully, before tilting forward once more and then pointing a tentacle questioningly at the Merman.

The Merman’s eyebrows came down again, and he put his head on one side as he said something. Cas huffed and repeated the gesture, before signing,

_I want to know if this is actually your name, or if I’m just calling you… Eelface, or something…_

All of a sudden, the Merman’s expression cleared. He folded over himself and then pointed at his own chest, making excited noises and then shaking his head backwards and forwards. What did that mean? Cas had no idea, but before he could sign his incomprehension, the Merman had spun around and was pointing to the red markings on his shoulder, the ones that Cas had noticed before, back when they’d still been separated by a firm barrier of coral. Cas experienced a sudden, dizzying sense of unreality. He could hear the sounds of the other Merpeople still on the far side of the coral, talking and calling to each other as usual. Surely there was only so much time before they came in search of the Merman? His sense of disconnection increased; they’d kill him, certainly. He felt fear winding its way up his gut, a little delayed but finally arriving. Should he flee? He pushed the impulse away and tried to focus on whatever the Merman was trying to tell him; if their time together was limited – if his time left  _alive_ was limited – then he wanted to make the most of it.

The Merman was pointing to the markings on his back and making the same sound, over and over. The marks looked raised and red, and Cas realised that they were scars; he’d heard of this practice, from the Octopeople Warriors. Apparently, the barbaric Merpeople scored their skin with shale, to leave permanent designs. The Merman’s scars were in a pattern that Cas, could, of course, make no sense of: half a circle, three lines attached to a long vertical line, a strange triangle and a zigzag. DEAN. The merman was still making that noise, slower now, sounding it out as he moved his finger along the markings on his shoulder – and in a rush, Cas understood. The markings were the sound and the sound was the markings – one signified the other!

The realisation spun Cas’ brain. This was sophistication the like of which the Octopeople couldn’t hope to match. To be able to communicate with sound, and to be able to parse that sound from markings? Amazing, Cas thought. Amazing, and beautiful.

“Dean,” the Merman said. “Dean. Dean.”

Cas felt the desire to run a tentacle along the marks as the Merman spoke them. He wondered how the noise was related to the markings. Did the pattern show the word as a whole? But the way that the Merman moved his finger along them at the same pace each time seemed to show that each separate mark was a different part of the noise. Cas shuddered his back tentacles in mingled awe and slight terror. What his people could do with this innovation!

“Dean,” the Merman was still saying. Cas wondered what it meant.

The Merman turned round, and pointed a finger at his chest.

“Dean,” he said again, and bared his teeth. Cas wiggled one of his tentacles excitedly in understanding.

 _The noise is your name!_ he signed.  _Your name is…_ Cas paused for a second, and then slowly sketched the half-circle that was the start of Dean’s name with his dominant tentacle. Dean’s teeth-baring increased, and he moved his head again, only this time it was up and down instead of side to side.

“Dean,” he said, and Cas sketched the half-circle along with him. The movement was meaningless in the language of the Octopeople, but in Cas’ personal language, it now meant  _Dean._

Cas met the Merman’s eyes, and decided the time was right to try baring his teeth. He curled his upper lip back, exposing his flat incisors and sharp canines.

Immediately, Dean pulled back a little way, his expression flitting too quickly for Cas to follow – eyebrows down, mouth open, eyes narrowed, hands raised in a stance of defence…

Cas stopped showing his teeth and began signing quickly:

 _Dean Dean Dean Dean Dean,_ he said, the one thing that he knew Dean recognised. He saw the change in Dean’s expression, the loosening of his muscles, with relief.  _I was just copying you,_ he signed confusedly. _Maybe I did it wrong._

Dean was drifting closer again. He started speaking, ending the sentence with the one sound that Cas recognised.

“Dean,” the Merman said, pointing to himself. Then, he pointed his finger at Castiel, and tilted his head to the side whilst saying something else.

 _You want to know my name?_ Cas signed.  _It’s Cas. Cas. Cas. Cas. Cas. Cas. Cas. Cas._

He signed it again and again, slower each time. Dean was watching him with total concentration, his eyes focused and intense. Cas’ name wasn’t especially complex, using only one tentacle, but he still wasn’t sure how Dean was ever going to be able to get it.

 _Cas,_ he kept saying, anyway.  _Cas Cas Cas Cas Cas. Cas._

Finally, Dean waved his arms, poked out his tongue, and lowered his eyebrows. Cas stopped moving, and Dean wiggled his head up and down. Then, in a move that Cas definitely hadn’t seen coming, Dean tried to say Cas’ name – but with his Merman’s tail, flicking the end as best he could. It came out garbled and strange, looking more like  _dogfish_ or possibly  _egg._ Cas waved his tentacles in laughter, and Dean was showing his teeth again, making those happy raspy noises in his throat. After a few seconds, he said something, and then dropped down to the ocean’s sandy floor. Cas watched him, feeling his own eyebrows pull down slightly in confusion as he did so. The Merman’s expressions were catching, it seemed.

Dean was obviously thinking hard. He looked up at Cas and pointed at him, his head on one side – asking him to repeat his name, Cas thought.

 _Cas,_ he signed again. Dean pulled his bottom lip inside his mouth, biting down on it with his top teeth. Cas watched the expression in fascination. Dean’s face was so fluid, the emotions gliding over it like the flutterings of a Spanish Dancer moving through the water. Dean was drawing his finger across the sand, leaving a marking – another half circle, only this time the other way around, and left open. He glanced back up at Cas and lifted his hands, rolling his two index fingers over each other in a looping circle. What could that mean? Cas remained still, waiting for Dean to try to explain. After a moment, Dean pointed to Cas, put his head on one side, and rolled his fingers over.  _Again_ , Cas realised. He wants my name again. He signed it, and Dean nodded his head, making another two markings in the sand.

He made a noise, and then looked up at Cas, who blinked. Dean made the noise again, and then ran his finger under the pattern in the sand. Next to the open half-circle, there was another strange triangle, and a soft double-curve, like the body of an eel.

“Cas,” Dean said, moving his finger along the drawing as he made the sound, and then pointing at Cas. “Cas. Cas.”

Cas liked how it sounded, moving from the back of Dean’s throat to the front of his tongue. And Cas supposed that the markings in the sand did look a little like the way he signed his name – the curve, the two sharp lines, then the double curve…

 _Cas,_ he signed, and Dean exposed his teeth.

“Cas,” he agreed.

They stared at each other for a long moment. Cas had never felt so exhilarated. His frantic heartbeat had slowed closer to normal now, but he could still feel a tingling in his fingers and the tips of his tentacles. Every now and then he kept getting a little spasming shock across his chest, because he was  _talking_  to the Merman – he was talking to  _Dean._ Dean knew his name. Dean could  _say_ his name. This was insane. This was utterly crazy. Cas stared at Dean, and knew that even if it were insane and crazy and a whole load of other things, it was also the best moment of his entire life.

From over the coral, Cas could hear the sound of the other Merpeople getting louder. He glanced over his shoulder fearfully, and then met Dean’s eyes; unable to communicate his panic, he began to cast around for a different place to hide. Dean seemed to catch his mood; he began to call, a long string of vocalisations. When he’d finished, a single Mermaid’s voice answered him, and then the noise subsided back to the previous low chatter. Cas sighed with relief.

After a moment, he looked up, to find Dean watching him. Cas was flattered to see that Dean’s eyes were full of interest; he seemed to be studying Cas’ tentacles, figuring out how they worked. When he realised that Cas was watching him again, Dean pointed to his own throat, and then to Cas, and then shook his head from side to side, before tilting it like he always did when he was asking a question. Cas raised his tentacles to sign.

 _Are you asking about vocalisation?_ he asked. He thought that was what Dean wanted to know, so he moved slowly closer and then opened his mouth, so that Dean could see inside. A strange, nuanced expression crossed Dean’s face before he leaned closer, and peered inside. When he pulled back, he looked confused, Cas thought. Cas moved even closer – now they were within touching distance. Cas could see Dean tense up, so he signed Dean’s name reassuringly, and then lifted a single tentacle – gently, slowly, ready to back away if Dean reacted badly – and lightly touched it to the side of Dean’s neck, where his gills were gently fluttering as water passed through them.

 _I’m made differently to you,_ he signed.  _I can’t make noises with my throat, I can only breathe with it._

Dean touched a hand to his gills, in the exact place where Cas’ tentacle had been seconds before. After a moment, his face changed; it seemed to light up, and Cas knew that Dean had understood. The Merman bared his teeth again, and Cas found himself trying to mirror the gesture – but it still didn’t feel quite right. Dean made his happy rasp sound, and came even closer, putting his hands out. Suddenly, his thumbs were touching Cas’ face, at either corner of his mouth; gently, Dean pulled his thumbs upwards, stretching Cas’ lips wider. Dean said something, his voice lower than before, his own mouth still curved up. He repeated the word over and over, until Cas could make sense of it.

“Smile,” Dean said. “Smile. Cas smile. Dean smile. Smile.”

Cas raised his hand, and drew an upwards curve with one finger.

 _Smile,_ he thought, as he did so.

“Smile,” Dean repeated, making the same gesture along with the sound.

They were still close together, close enough that Cas could see the colour of Dean’s eyes – greener than seaweed – and close enough that Cas was thinking about how gentle Dean’s touch had been on his face, how smooth his skin had felt. Cas took a deep breath, and stopped smiling. His cheeks were already a little sore with the effort.

From over the coral, the sounds of the Merpeople were getting louder again. Cas knew that Dean had to go back to them, and there was no way that he could stay here and be seen. He’d have to flee, and as fast as he could. And yet – he couldn’t just leave, not without some kind of goodbye, or… or a promise to meet again. But how could he ask for that, when Dean didn’t understand a word he was saying? He began to drift away, and Dean’s expression flattened, the look in his eyes becoming serious. He said something, looked over at the coral, and then flapped his arms as though pushing Cas away.

 _I know,_ Cas signed.  _But I have to see you again. Please can I see you again?_

Dean was watching him, looking lost. He met Cas’ eyes, and said something, tilting his head. Cas thought he saw his own longing reflected back at him in Dean’s expression, but he couldn’t be sure – he was still so bad at reading the Merman’s face.

 _I want to see you again,_ he signed, and then remembered the gesture that Dean had used for again earlier. He lifted his hands and circled his index fingers, just as Dean had, as though rolling a strand of seaweed around them.  _Again?_

 _Again,_ Dean signalled back, and his downturned mouth was suddenly curving upwards again.  _Again. Again. Cas again._

 _Dean again,_ Cas agreed.  _Dean again._

The Merpeople must have been nearly upon them. Just before Cas turned to go, Dean lifted up his palm, and said something as he held it in the air. Cas stared at it, wondering what Dean was trying to say, his heartrate speeding again as the threat of being caught heightened and heightened – but he couldn’t leave when Dean was still trying to say – what?

 _Dean?_ Cas signed, his head on one side. Dean reached down with his other hand, grabbed Cas’ wrist and lifted it, pressing their two palms together.

 _Together?_ Cas signed with his tentacles, and Dean said something, and smiled one more time, before breaking away and pushing at Cas’ shoulders, telling him to go. Cas, his palm buzzing and brilliant, turned quickly and began to glide away, his tentacles pushing his body over the sand. He risked stopping once, to glance back over his shoulder. Dean was swimming back over the coral towards his friends, halting their progress and turning them around, his powerful green-brown tail waving confidently. When they were all heading back to the plateau, Dean turned, and looked back at Cas. They stared at each other for a long moment, the intensity of their gaze making the distance between them lessen to nothing.

 _Cas again,_ Dean signed.

 _Dean again,_ Cas replied.

They each raised a palm, a salutation, a promise.

_Together._


End file.
